While the term "lecithin" classically refers to phosphatidylcholine, in commercial parlance "lecithin" is understood to include the mixture of phosphatidylcholine and other phosphatides such as phosphatidylethanolamine and phosphatidylinositol with minor constituents including sterol and carbohydrate. These and other examples can be found in the Food Chemicals Codex. The most abundant source of lecithin is an oil containing concentrate which is recovered in the degumming of vegetable oils and is comprised of lecithin and associated phosphatides. This concentrate usually comprises about 60 to 65% mixed phosphatides (lecithin along with naturally occurring minor constituents) and 35 to 40% oil from the degumming process.
It has been known that lecithin functions as an anti-oxidant in polyunsaturated fatty oils, in mineral oils and even in gasoline. It is also known that lecithin counteracts the corrosion of metals exposed to moisture and to solvent/moisture systems. However, the level of protection previously afforded by lecithin compositions has proven to be insufficient for commercial utilization.